A split rail power supply (also referred to here as a dual, dc power supply) is needed to supply power to a signal controller for a Class D audio power amplifier, e.g., +5 Vdc, −5 Vdc. The controller produces the audio signals that are needed to drive the power stage transistors (of the power amplifier). The audio signals are typically centered about ground (zero Volts), but available power sources in many applications typically only provide a single, positive voltage relative to ground, e.g., a battery, or the output of an AC-DC wall power adapter. A power conversion circuit may be used in such cases, referred to as a split rail power supply, that converts the single, positive input voltage of the power source into positive and negative dc output voltages, or top and bottom rail voltages. The top and bottom rail voltages are produced relative to an output ground node that is at a different potential than the ground node of the power source.